"Tomcat" or "tom cat" refers to a male cat, usually an outdoor or
stray cat.
A tomcat is a cat with large
puffy cheeks, mostly made up of scar tissue. They are fighting cats, hence the scarred face.
Most (but not all) tomcats are infected with FIV, feline immunodeficiency virus. FIV is
sometimes referred to as fighting cat disease. Which is transmitted through bodily fluid (ie. saliva or blood)